1. Field of the Invention
This invention relates to an image reading apparatus for reading a plurality of images recorded on an original document.
2. Description of the Prior Art
A microfilm scanner which reads images photographed on a microfilm is known as one of various known versions of the image reading apparatus.
The microfilm scanner is provided with a screen for allowing projection thereon of images photographed on a microfilm as an original document and a photoelectric conversion element for converting a projected image into electronic information and is adapted to image process a signal from the photoelectric conversion element and then forward the signal to an external printer, for example. This printer plays the part of printing the image on a recording paper.
Some microfilms are used for photographing therein information borne on checks. Oblong sheets of paper which measure 32/3 inches.times.17 inches are generally used for checks. In a roll of microfilm, the information, i.e. the obverse image and the reverse image of the check as a pair, are photographed in one frame and arranged in parallel relative to the direction of the width of the film.
For the purpose of enabling the information, i.e. the obverse and reverse images, of one check photographed on the microfilm to be printed out in one recording paper, the recording paper is required to be an oblong sheet of paper of a special size. The printer to be used in this case is at a disadvantage in requiring the use of a feed paper cassette and a recording paper conveying system which are different from those used in the printer for reproducing an image on a recording paper of a standard size. Moreover, the special size recording paper has the problem of being difficult to file.
Generally a rotary camera is used for photographing checks on the microfilm in such a manner that the obverse and reverse images of each check as a pair are arranged laterally in the width direction of the film (hereinafter the microfilm produced in this pattern will be referred to as "duplex type microfilm"). When the check being photographed happens to be inclined, it is photographed in the inclined state.
The obverse image and the reverse image photographed from the inclined check are inclined in mutually opposite directions. When these images are read out by a microfilm scanner and printed on recording paper, the printed observe and reverse images are oppositely inclined and, therefore, unsightly in appearance.
When a plurality of checks gathered in a stack are to be photographed on a microfilm, there are times when some of them are possibly placed upside down in the stack. The obverse and reverse images photographed from such a stack of checks into a microfilm are in the order of obverse and reverse sides in some cases and in the order of reverse and obverse sides in other cases relative to the sequence of the reading of the information by the microscanner. As a natural consequence, the images reproduced on the recording papers are in the order of obverse and reverse sides in the former cases and in the order of reverse and obverse sides in the latter cases. Thus, the information obtained on the recording papers lacks uniformity.
In order to solve the problem described above, a method which comprises severally reading out a plurality of images photographed on a given frame of microfilm, putting these images to temporary storage in a memory, synthesizing them during the process of retrieval from the memory, and printing the synthesized images has been previously used. This method, for example, is aimed at arranging images of information in parallel and printing them so arranged on ordinary size recording paper or, when the reverse and obverse images are placed in the reverse order, changing the order of reading of these images and printing the images in the changed order.
When a microfilm happens to contain among the images photographed therein those which are inclined, this method operates with the steps of preliminarily scanning the images and detecting those inclined images, severally correcting the inclinations of the detected images, and reading again severally the images inclusive of those with corrected inclinations. When one frame of film contains a plurality of images, however, the reading of images consumes a lot of time because the preliminary scanning intended to detect an inclination in an image must be carried out once for each of the plurality of images and the regular scanning must be carried out once for each of the images to be involved.
Thus, any of such conventional methods as described above is at a disadvantage because the reading of images consumes a lot of time and the operation of reading does not proceed smoothly because the scanning operation for reading an image must be performed as often as many images are photographed on one frame of film.